app.yaml : wildcard in URL with static_dir?

Question

My attempt at matching a regex as directory name in app.yaml doesn't work :

- url: /v1_.*
  static_dir: static/v1
  expiration: "364d"

Although this official spec says regex syntax is supported. Is there a way to make this work ?

I.e. /v1_2014-01-29/img/logo.png should match the static file /static/v1/img/logo.png.

Trivia

I use Google App Engine to serve a Go webapp.

I'd like to maximize browser cache longevity, minimize number of requests and still serve the fresh versions of my css/js/png, and I believe revving filenames is a best practice to achieve this. Also as adding a variable querystring (/v1/img/logo.png?2014-01-29) might cause proxy and cache problems, I prefer to show a variable directory name (/v1_2014-01-29/img/logo.png), pointing to the same underlying server dir.

Answer 1

After olivierdm's answer I changed my yaml into :

- url: /v1_.*_
  static_dir: static/v1
  expiration: "364d"

and my html templates to produce /v1_2014-01-29_/img/logo.png.

Basically, the extra arbitrary character underscore _ forces .* to match 2014-01-29, not the empty string.

Now every time I want the visitors to reload the static files, I just change the date in the tempating (I don't touch the app.yaml anymore). Also, any accidental request to an "outdated" URL will still succeed and serve the fresh resource.

Answer 2

Seems to me that whatever part of the URL that is beyond the match of the url definition (which matches from the start) is appended to the static_dir.

So the following handler should match /v1_2014-01-29/img/logo.png if the file path is static/v1/img/logo.png (tried with Python):

- url: /v1_(\d+-?)+
  static_dir: static/v1